Graft polymers examples

Functionalization of the polymer has been widely employed in binary nanocomposites to improve the polymer/filler interactions and thus maximize the load transfer. Functionalization also serves to enhance the compatibility between the two components of polymer blend. Many grades of functionalized polymers are now available, including maleated grades and silane-grafted polymers. Examples of functionalized matrices studied in ternary nanocomposite studies include PP-g-MA [41], PP-g-VTEOS [27] and examples of functionalized elastomers include SEBS-g-MA [8,49,65], EPR-g-MA [19,44,65], POE-g-MA [75], and EPDM- -MA [64]. It is also important to note that only nonpolar matrices and elastomers require functionalization, as opposed to polar polymers like PA6, which present natural interactions with polar fillers such as silica particles and clay platelets. 

An effective method of NVF chemical modification is graft copolymerization [34,35]. This reaction is initiated by free radicals of the cellulose molecule. The cellulose is treated with an aqueous solution with selected ions and is exposed to a high-energy radiation. Then, the cellulose molecule cracks and radicals are formed. Afterwards, the radical sites of the cellulose are treated with a suitable solution (compatible with the polymer matrix), for example vinyl monomer [35] acrylonitrile [34], methyl methacrylate [47], polystyrene [41]. The resulting copolymer possesses properties characteristic of both fibrous cellulose and grafted polymer. 

While polymers most commonly consist of carbon, nitrogen and oxygen, hybrid materials containing metals or other elements represent an important class of materials [76-78]. Hybrid materials too have been used as hyperbranched grafts. Two examples of such materials are described here. The first is a polysiloxane graft. The second is a dendritic coordination polymer based on a thermally and oxygen stable Pd(II) pincer complex [79]. 

SIP-driven polymer brush library fabrication leverages the fact that the polymerization initiation species are permanently bound to the substrate. Since the initiators are tethered, controlled delivery of monomer solution to different areas of the substrate results in a grafted polymer library. In NIST work, initiators bound via chlorosilane SAMs to silicon substrates were suitable for conducting controlled atom transfer radical polymerization (ATRP) [53] and traditional UV free radical polymerization [54, 55]. Suitable monomers are delivered in solution to the surface via microfluidic channels, which enables control over both the monomer solution composition and the time in which the solution is in contact with the initiating groups. After the polymerization is complete, the microchannel is removed from the substrate (or vice versa). This fabrication scheme, termed microchannel confined SIP ([t-SIP), is shown in Fig. 10. In these illustrations, and in the examples discussed below, the microchannels above the substrate are approximately 1 cm wide, 5 cm long, and 300-500 [tm high. 

Grafted Polymers. Due to the special chain structure ABS terpoly-mers have been widely modified by grafting vinyl monomers onto the main chain. We emphasize that the method how ABS itself is obtained is addressed sometimes as grafting styrene and acrylonitrile onto a butadiene rubber. Here we focus on grafting reactions on the ABS itself. Some examples of ABS grafted polymers are shown in Table 8.7. The pending acid functionalities may be allowed to react with amines and other compounds (45). 

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